Biomass Boilers

 Windhager biomass boilers

Windhager is one of Europe’s leading manufacturers of carbon neutral wood pellet and log gasification boilers. Founded in 1921 by Anton Windhager in his home town near Salzburg, Austria, the company has decades of knowledge and experience, and the name Windhager is inextricably linked with quality, innovation and energy efficiency.




Hybrid wood and pellet burner in one - output range 33 - 56kW

With hybrid technology, DuoWIN combines heating with wood and pellets in one unit. This sophisticated biomass boiler system allows users to either use logs or wood pellets and its intelligent fuel switching detects when the wood gassifier is in burnout and switches to pellet operation, either automatically or at a desired time.

The DuoWIN system is based on two of Windhager’s proven biomass boilers, the compact log boiler LogWIN Klassik and the recently launched compact BioWIN2 wood pellet boiler. It takes up just 4.19 sq m of space.

The DuoWIN is available as either a comfort or energy-optimised variant. The PowerBoost function can meet short-term higher heat demands up to 56kW. With the energy-optimised version, the DuoWIN’s pellet operation is up to 25% more efficient than conventional combination boilers. Available in four models from 33kW-56kW output, the DuoWIN has a filling volume of 145 litres for 50cm split logs and 164 litres of wood pellets, the feed for which can be either manual or fully automatic.

Within DuoWIN there are two independent heat exchanger systems that ensure maximum reliability, yet with a smaller space requirement compared with other combination solutions. Both the wood combustion chamber and the stainless steel pellet burner bowl are non-wearing parts and are included in Windhager’s five-year warranty. The DuoWIN’s ignition elements ignite silently, are robust and maintenance-free and are also covered by the warranty.

One special feature is that you can upgrade any time to the DuoWIN if you have Windhager’s LogWIN Klassic log boiler as it is “pellet ready”, meaning that the pellet boiler BioWIN2 can be added at a later date.

The LogWIN Klassic has a large filling chamber opening for easy access to logs, and has a detachable ash pan for easy removal. The log boiler also features automatic ignition in the DuoWIN, meaning that no kindling is required to start burning.

BioWIN2, the incorporated wood pellet within DuoWIN, has very long maintenance intervals. Its robust stainless steel burner with LowDust technology burns so cleanly that the pellet boiler is well below the international emissions standards.



Wood pellet boiler - output range 2.9 - 60kW

With a wide range of sizes available, there is a BioWIN pellet boiler that's just right for installations ranging from the small domestic setting through to larger domestic and smaller commercial installations. Its compact design means it can be installed in the smallest of boiler rooms, and where access is an issue the boiler can be dismantled into several easily transportable sections.

It features a fully automatic patented pellet feed with from one to eight suction probes for easy pellet supply. The BioWin also features an innovative fully automated cleaning system so once commissioned you don't need to worry about anything else. Features include fully automated burner bowl ash removal; fully automated heating surface cleaning to ensure high efficiency and low fuel consumption; fully automated ash removal for long intervals between maintenance, meaning the BioWIN Exclusiv needs only be emptied between 1 and 3 times a year.

The boiler features a large reserve supply container of up to 150kg of pellets which enables long, uninterrupted burning phases for greater efficiency.



Wood pellet boiler - output range 3 – 26kW

The BioWIN2 is the new generation BioWIN boiler, with five models to suit different individual needs and with a very small footprint for its output, it can fit the most compact spaces. You decide whether your BioWIN2 is filled automatically or by hand. Due to it's generously sized integral hopper if you fill it by hand you'll only need to replenish the pellets every 5 to 20 days (depending on output and hopper capacity).

The Klassik, Klassik-L, Exclusiv-SL and Exclusiv-S are all manual feed with pellet capacities ranging from 107kg to 200kg in the integral hopper. The Exclusiv is a fully automatic feed boiler. You can choose to upgrade from a manual Exlusiv to an auto-feed model after the initial installation.

The BioWIN2 is an extremely low maintenance boiler, with the ash container needing to be emptied as little as once or twice a year.



Fully automatic wood pellet heating boiler - output range 4.7 – 12kW

This striking pellet boiler comes in a choice of four colours and features an attractive double glazed combustion chamber window, and is designed for the living room rather than the boiler room. You can spend cosy evenings in front of the fire while also heating your hot water and entire home in a low cost and user-friendly manner.

It features a patented air curtain which flushes air to just behind the glass panel which gives you a clear view of the flame for long periods and means the window hardly ever needs cleaning. The boiler features a double front door which, with the double glazed window, prevents dangerous surface temperatures on the boiler.

The FireWIN can be operated with or without an external supply of combustion air, and is available in both manual feed and automatic pellet feed, depending on your preferences and available space for a pellet store. It's extremely low maintenance with the ash pan only needing to be emptied 2 - 3 times per year due to its automatic ash compaction feature and large integral ash pan. 

It's also proven to be the quietest living room pellet boiler on the market.

Yorkshire Heat Pumps installers are WIN3 qualified so are able to service Windhager biomass boilers in line with the requirements of the manufacturer warranty.


ETA biomass boilers

ETA Heiztechnik GbmH (to give it's full name) is an Austrian company specialising in the design and production of high specification biomass boilers. Established in 1998, ETA is a major manufacturing player in the renewable energy heating business. With a growing product portfolio of log, wood chip and pellet boilers, and models ranging in size from 7kW – 350kW, they are suitable for domestic installations of all sizes and larger commercial or industrial applications.



ETA PU – PelletsUnit Biomass Pellet Boiler

7, 11 and 15kW - the small 'smart' pellet boiler

The ETA PU is the perfect solution if you haven’t got enough space for a separate boiler room as it doesn’t require one. What’s more this can also save you money on fuel costs as you avoid the heat loss associated with an external boiler room outside the insulated shell of your home. The stylish design, with a choice of four front panel finishes, can sit comfortably within your utility or living room, and simply requires an independent combustion air supply. It’s just 105 cms wide x 58 cms deep x 107 cms high.

A pellet storage hopper either 1.6 x 1.6 metres or 2.5.x 1.0 metres (depending on boiler size) can be located on the other side of the house as the pellets are conveyed to the boiler once a day via two plastic hoses.

An intuitive, colour touch screen control unit is located on top of the boiler which uses pictures and text to make operation of the boiler child’s play. You can also control your boiler via SMS when not at home.

The ETA PU has Lambda control for maximum efficiency and minimum emissions, automatic ignition, integrated return temperature riser control, low power circulation pump with mixing valve and an 18 litre expansion vessel. A 3 bar safety valve and switch over valve for the hot water tank are included as standard within the boiler, all of which results in lower plumbing and electrical installation costs.

This is a very low maintenance unit with fully automatic de-ashing with the integrated cleaning system, and a patented rotating grate with self-cleaning, which stirs the fire and ensures best possible fuel utilisation. The ash tray needs emptying just twice a year and simply slides back behind the front door panel.


ETA PC – PelletsCompact Biomass Pellet Boiler

20, 25 and 32kW - the small 'large' pellet boiler

The ETA PelletsCompact is a space saving wonder which can be fitted right up to a wall. It’s just 111 cms wide x 76 cms deep x 130 cms high which means it can fit comfortably in most homes. Its pellet store need be no larger than an oil tank and can be situated up to 20m from the boiler.

Controlled by a 15 cm touch screen with intuitive graphics and icons, it takes just a couple of taps of your finger to increase or decrease the temperature. The controls feature a ‘holiday mode’ where you can set the start and finish dates of your holiday and run the boiler in ‘set-back’ mode while you’re away and reactivate your usual settings for your return home, or alternatively, you can operate your boiler remotely via smartphone or computer over the internet – all you’ll require is an internet connection available at your boiler, via WiFi for example. All ETA customers have free access to the communication platform at  

The ETA PC comes with many outstanding features as standard including a Lambda probe for maximum efficiency and minimum emissions, automatic cleaning and complete combustion control system, which minimises emissions and maximises operating efficiency.

Routine maintenance is very straightforward thanks to the boiler’s patented rotating grate which cleans itself as it burns and the ash generated is automatically fed into the ash bin at the front of the boiler. This needs emptying just 3 – 5 times a year and should you forget to empty the ash bin you will receive an email reminder.

The ETA PC can operate as a stand-alone boiler, but there are many advantages to adding a buffer tank to the boiler set up. A buffer tank can store the entire boiler output and provide exactly the amount of heat required for your heating and hot water needs both at times of high heat demand and at times of low heat demand when the system is only providing hot water. Having a buffer tank reduces the frequency of boiler stop/starting and thus saves fuel. 


ETA PE-K Biomass Pellet Boiler

35, 50, 70 and 90kW - technology that’s built to last - suitable for larger domestic properties and commercial use.

The ETA PE-K offers heating output from 35kW up to 90kW and features a complete control system that can incorporate a solar heating system or small local heating network. The boiler features active monitoring of all functions and remote maintenance via GSM and the internet.

Operating reliability is ensured by comprehensive measurement and reporting on the status of all boiler operations – such as draught fan speed, power consumption of electric motors, air valve position, residual gas in the flue gas, and boiler temperature.

The 35 and 50kW boilers measure 61 x 110 x 157 cms and the 70 and 90kW measure 71 x 125 x 179 cms so can be accommodated in a plant room or garage along with the buffer tank. The pellet store can be up to 20m away from the boiler, which has a large 60kg capacity integrated pellet hopper  which reduces pellet transport from the store to one or two ten minute feeds for the 35kW unit and three to four ten minute feeds for the 90kW.

The ETAtouch control system features a touchscreen with self-explanatory images and icons. The boiler can be monitored and controlled remotely using a PC, smartphone or SmartTV, and an optional GSM modem also allows the boiler to issue fault messages by SMS.

The boiler has a ceramic-lined combustion chamber with secondary air turbulence which guarantees a clean fire with a high burnout temperature, while the flue gas recirculation minimises grate temperatures to prevent slag forming. It also has a tilting grate which tilts at output-based time intervals to remove ash from the combustion chamber. All these features contribute to the boiler’s reliability and efficiency.

A Lambda probe is fitted as standard to ensure clean combustion and high fuel efficiency. Heat exchanger cleaning is fully automated with a spring mechanism to jolt the turbulators and remove any fly ash. What’s more, two discharge screws automatically transport grate and fly ash into the detachable ash box for easy cleaning.


ETA HACK Wood Chip or Pellet Boiler

20, 25, 35, 50, 70, 90, 130 and 200kW - the ETA HACK can burn either wood chips or pellets, giving you maximum flexibility.

This ‘smart’ boiler features automatic fuel recognition. With the Lambda probe fitted as standard, the ETA HACK’s control system measures the residual oxygen in the flue gas and adjusts the fuel input and air supply according to the energy density of the fuel. This ensures the ETA HACK operates with maximum efficiency and minimum emissions throughout the season, whether you use moist spruce chips, loose dry wood waste or dense pellets.

It features a clever fuel conveying system using top quality spur gears that have an efficiency of over 95%. Combined with the system’s progressive screw this can lead to a reduction in electricity consumption of around one third.

The electricity required by the boiler’s motor is constantly monitored so any blockages or resistance build-up in the feeder screw are immediately registered, automatically reversing the screws up to three times if necessary. At the same time, the floor agitator is decoupled via a clutch so the motor’s power is exclusively focused on unblocking the screw. Any jammed pieces of wood can be loosened this way so fuel transport can resume once more.

ETA sets new standards in safety with the airtight one-chamber rotary valve which protects against back-burn. It can never be in a position with a direct connection between the combustion chamber and the fuel store. No hot gas can enter the fuel conveying system so ignition of the wood chips is impossible. This is the most reliable protection available against burn-back.

The one-chamber rotary valve can handle wood chips up to G50 in size and any larger pieces of wood are cut by a hardened replaceable blade on the edge of the chamber.

The boiler has a refractory-lined combustion chamber and secondary air turbulence to ensure a clean fire with high burnout temperature and a tilting grate which is activated after a controlled ember burnout period, to remove ash automatically from the combustion chamber.

Cleanliness is important for efficient operation of the boiler thus the ETA HACK features automatic, complete ash removal, from the grate to the heat exchanger. Its tubes are automatically cleaned by agitated turbulators and the grate is also tilted on a regular basis. Two motor-driven discharge screws transport the ash from the collecting area below the grate and below the tubular heat exchanger to the ash box. This is situated at the front of the boiler for easy removal and emptying.

The boiler is controlled via the ETAtouch control system featuring a touchscreen with self-explanatory images and icons. The boiler can be monitored and controlled remotely using a PC, smartphone or SmartTV, and an optional GSM modem also allows the boiler to issue fault messages by SMS.

The boiler can be supplied with the stoker on either the right or left hand side so it can work in different spaces.  


To find out more, contact us here, or call today on 01423 788699 for a 'no obligation', free fact-finding conversation.

How do Biomass Boilers Work?

Unlike a wood burner, biomass boilers are electronically controlled. Wood pellets, wood chips, cereals, miscanthus or other biomass fuels are used which are ignited by an electronic probe.

Combustion temperatures are monitored via thermostats which automatically adjust the speed at which the fuel is fed into the firebox. This heats water within the boiler which is then circulated around the heating system, maintaining the desired temperature.

Everything from ignition, to timers and temperature is controlled by an easy-to-use control panel integrated onto the boiler, and just like a conventional domestic boiler, the system uses room thermostats to regulate the system and maintain a comfortable room temperature.

Which biomass boiler is right for you?

The choice of boiler is determined by a number of factors. The heat and hot water demand of the building will dictate the size of biomass boiler required, but the space you have available will also be a factor, as will the heating system the boiler will integrate with.

Biomass boilers come in all sorts of shapes, sizes and colours from the more industrial looking to streamlined models which can sit comfortably in your living room. Some feature a glass panel allowing you to see the burner in action.

There are also multiple options on fuelling your boiler. In the case of a pellet stove, which is the most energy-efficient, you can opt for a manual feed system, whereby you empty bags of pellets into a small internal hopper, or alternatively, if space is no barrier, you can install a pellet store which holds several tonnes of pellets which are then screw-fed or vacuum-fed into the boiler when required. The advantages of this include the cost efficiency of buying pellets in bulk, which are blown from a tanker directly into the store, as well as knowing you don't have to be at home to top up the boiler to ensure your heating comes on when you want it to!

At Yorkshire Heat Pumps, we do not favour one particular make or model and just recommend that, but rather we listen to your requirements and understand your lifestyle and life-stage before identifying the best solution for you and your home. Of couse, the detailed Heat Loss Survey we recommend you undertake on your property is all important in ensuring we size the boiler correctly. Underspecify, and your home may not be warm enough. Overspecify, and you will be paying for capacity you don't actually need.


RHI eligibility

Subject to certain air quality and fuel sustainability criteria, the following biomass technologies are eligible for Renewable Heat Incentive (RHI) payments:

  • Biomass-only boilers (covers all solid biomass including logs and chips)
  • Biomass pellet stoves with back boilers
  • Condensing biomass boilers